Before the new road linking the R671 to the town could proceed, archaeologists uncovered the scattered remnants of a fulacht fia, one of the most common yet persistently mysterious monument types in the Irish landscape. A fulacht fia is, in essence, a prehistoric cooking or heating site, typically consisting of a mound of fire-cracked stones discarded after repeated use, alongside a water-filled trough into which those heated stones were dropped to boil liquid. They are found in their thousands across Ireland, usually in low-lying or waterside ground, and date mainly to the Bronze Age.

The Killincarrig site, excavated in 2003 under licence prior to the carriageway works, revealed three separate spreads of burnt mound material rather than a single concentrated deposit, suggesting either repeated activity across the area or the gradual dispersal of material over time. An associated trough was also uncovered, along with a number of post-holes, which hint at some form of timber structure connected to the site's use, though the precise nature of that structure remains a matter of interpretation. The excavation was reported by Molloy in 2006, and the site carried the designation Site K within the broader road scheme investigations, a reminder of how much archaeology lies along the corridors of infrastructure projects that most travellers pass through without a second thought.